1. Field of the Invention
The present invention relates to high-frequency transmission lines and electronic devices, more particularly to a high-frequency transmission line for use in high-frequency signal transmission and an electronic device including the same.
2. Description of Related Art
As inventions relevant to conventional high-frequency transmission lines, signal lines described in, for example, International Patent Publication WO 2011/007660 and Japanese Patent Laid-Open Publication No. 2011-71403 are known. Each of these signal lines includes a laminate, a signal line, and two ground conductors.
The laminate is formed by laminating a plurality of flexible insulator layers. The signal line is provided in the laminate. The signal line is positioned between the two ground conductors in the direction of lamination. Accordingly, the signal line and the two ground conductors form a stripline structure. The signal lines described in International Patent Publication WO 2011/007660 and Japanese Patent Laid-Open Publication No. 2011-71403 are formed by laminates, and therefore, are thinner than the diameter of a typical coaxial cable. Accordingly, they can be disposed in a narrow space within an electronic device.
Incidentally, in some cases, it is desired to cross two signal lines such as those described in International Patent Publication WO 2011/007660 and Japanese Patent Laid-Open Publication No. 2011-71403. However, crossing two signal lines results in two laminates overlapping at a crossing portion of the two signal lines, hence a significantly increased thickness at the crossing. On the other hand, it is conceivable to provide two signal lines in a single laminate, so as to cross each other within the laminate. This results in a reduced thickness at a crossing portion of two signal lines in a laminate, but crosstalk occurs between the signal lines because the signal lines are opposed to each other.